如何将 AVAsset 转换为 CMSampleBuffer 帧？答案

【问题标题】：How do you convert an AVAsset into CMSampleBuffer frames?如何将 AVAsset 转换为 CMSampleBuffer 帧？
【发布时间】：2021-03-30 23:29:57
【问题描述】：

我的应用导入用户通过系统文件选择器选择的视频，它以AVAsset 的形式出现：

@IBAction func handleImportVideoButton(_ sender: Any) {
    let documentPicker = UIDocumentPickerViewController(forOpeningContentTypes: [.movie], asCopy: true)
    documentPicker.delegate = self
    present(documentPicker, animated: true)
}

// UIDocumentPickerDelegate callback.
func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
    guard let url = urls.first else {
        return
    }
    model.recordedVideoSource = AVAsset(url: url)
}

然后我如何将此AVAsset 转换为CMSampleBuffer 帧？最终目标是将CMSampleBuffer 帧转换为CGImages，这样我就可以考虑对每个图像帧进行机器学习分析。

【问题讨论】：

标签： ios swift avfoundation core-foundation

【解决方案1】：

这是未经测试的，但它应该为您提供如何解决此问题的要点：

let asset = AVAsset()
let reader = AVAssetReader(asset: asset)
guard let track = asset.tracks(withMediaType: .video).last else {
    return
}
let trackOutput = AVAssetReaderTrackOutput(track: track, outputSettings: nil)
reader.add(trackOutput)
reader.startReading()

// Get first sample buffer
var sample = trackOutput.copyNextSampleBuffer()
while sample != nil {
    // iterate over all buffers
    // sample = trackOutput.copyNextSampleBuffer()
}

【讨论】：